I have a 427 (did not build it) & it can twist to 7200 if I choose, but it makes me nervous. This is my first BBC... gotta love the pure torque. I hate adjusting the valves (solid) as someone said earlier... but other than that, seeing the difference from all of the SBC's I have had, I must say I like it. When I think of a 366, I recall a 2 ton truck we used to buck hay with... I think they made a decent dump truck eng back in the day too. You gotta love a high RPM SBC too... like the old DZ's... pretty cool.